Adjustable loading ramp



Aug. 9, 1955 c. E. WATSON ADJUSTABLE LOADING RAMP 6 Sheets-Sheet 1 Filed June 8, 1949 INVENTOP A 7'7'OQNEY CHARLES E. WATSON BY Aug. 9, 1955 Filed June 8, 1949 C. E. WATSON ADJUSTABLE LOADING RAMP 6 Sheets-Sheet 2 [NVENTOQ CHAR E5 E. W 50/\/ 5 @ZM HTTOIQNEV Aug. 9, 1955 c. E. WATSON ADJUSTABLE LOADING RAMP 6 Sheets-Sheet 3 Filed June 8, 1949 INVENTOR. CHA QLEfi E. WA 7250M Arm/3N5 Y United States Patent fifice Patented Aug. F, 195-5 ADJUSTABLE LOADING RAMP Charles E. Watson, La Grange, Ill., assignor, by mesne assignments, of one-half to Margaret Redick Pennington, Pittsburgh, Pa.

Application June 8, 1949, Serial No. 97,816

9 Claims. (Cl. 14-71) This invention relates to loading and unloading ramps and more particularly to power actuated ramps for bridging the space between stationary and movable platforms, although it may be employed with equal advantage for other purposes.

It contemplates more especially the provision of power form to the end of entailing appreciable time loss, labor and handling which defeats the purpose of their use. With the teachings of the present invention, the loading ramp is permanently mounted in a stationary platform for power actuation up or down and extension to bridge any intervening space between the fixed and movable platform, such as the floor of a vehicle.

To simplify the construction and operation of devices of this character, a hydraulic power source is utilized to raise and lower the ramp and to effectually control its position in any adjusted relation relative to the platforms to be bridged therewith. Ramps have been heretofore proposed, but they involved crude mechanical lifts and could be inclined up only and not at all downwardly which is important in some situations. Then, too, ramps of known design are not sufiiciently flexible to varying requirements and differences in loading and unloading facilities.

One object of the present invention is to simplify the construction and improve the operation of devices of the character mentioned.

Another object is to provide an improved loading ramp that bridges the intervening space between a fixed and movable platform at the same or different levels.

Still another object is to provide an improved loading ramp and power mechanism to effect the actuation there of.

A further object is to provide a loading ramp that is mounted in the shallow pit of a stationary platform for .power displacement at any angle of inclination to bridge an intervening space with a movable platform such as a vehicle or freight car floor.

A still further object is to provide a hydraulic actuator in conjunction with pivotally mounted rams for bridging the intervening space between fixed and movable platforms.

Still a further object is to provide a power actuated loading ramp with an adjustable apron for permanent mounting in a platform pit to bridge the intervening space with a movable platform positioned at varying relative levels.

Other objects and advantages will appear from the 11 following description of an the present invention.

In the drawings:

Figure l is a plan View of a loading ramp embodying features of the present invention, parts thereof being broken away to clarify the drawing.

Figure 2 is a sectional view in elevation taken substantially along line lI-Il of Figure 1, the ramp being shown in its horizontal and also diagrammatically in its elevated inclined position.

Figure 3 is a sectional view taken substantially along line III-J11 of Figure 1.

Figure 4 is a sectional view taken substantially along line IVIV of Figure 1.

Figure 5 is a plan view of a three section railroad ramp embodying features of the present invention.

Figure 6 is a front View in elevation of the three section railroad ramp shown in Figure 5.

Figure 7 is a sectional view taken substantially along line VII-VII of Figures 5 and 6.

Figure 8 is a sectional view taken substantially along line VIIIVHI of Figures 5 and 6.

Figure 9 is a sectional view taken substantially along illustrated embodiment of 'line l'X-IX of Figure 5.

Figure 10 is a sectional view taken substantially along line X- X of Figure 5.

Figure 11 is a sectional view in elevation taken substantially along line XI-Xi of Figure 5.

Figure 12 is a plan view of a still further modified embodiment of a loading ramp having an extensible platform which is advantageous in situations where the loading platform is an appreciable distance from a vehicle or a freight car platform with a substantial gap therebetween, the platform being shown in a fully extended position.

Figure 13 is a side view in elevation of the platform shown in Figure 12.

Figure 14 is a side view in elevation of the platform and foundation similar to Figure 13, but with the platform closed or in its fully contracted position, the loading platform being shown with dotted lines in an upwardly and also in a downwardly inclined position.

Figure 15 is a sectional view in elevation taken substantially along line XV-XV of Figure 12.

Figure 16 is a sectional view in elevation taken along line XVI-XVI of Figure 12.

Figure 17 is a top plan view of the loading ramp sling construction to which hydraulic rams are connected as illustrated in Figures 1 and 2.

Figure 18 is a front view in elevation of the sling shown in Figure 17.

Figure 19 is an end view in elevation of the sling shown in Figures 17 and 18.

Figure 20 is a front view in elevation of the ramp pump assembly which comprises the actuator for the hydraulic instrumentalities which comprise the actuating medium.

Figure 21 is an end view in elevation of the ramp pump assembly shown in Figure 20.

Figure 22 is a front view in elevation of the double valve assembly mechanism comprising the control for the ramp pump assembly.

Figure 23 is an end view in elevation of the double valve assembly control shown in Figure 22.

Figure 24 is a schematic hydraulic circuit diagram for a two-ramp actuator.

Figure 25 is a plan view of a loading ramp similar to Figures 1 and 12, but having in addition thereto a double apron that is of extended depth and is equipped with a power actuator to raise and lower this apron.

Figure 26 is a sectional view in elevation taken substantially along line XXVI-XXVI of Figure 25.

Figure 27 is a fragmentary sectional view in elevation taken substantially along line XXVII-XXVII of Figure 25.

Figure 28 is a fragmentary sectional view in elevation taken substantially along line XXVIII-XXVIII of Figure 25.

Figure 29 is a top plan view similar to Figure 25 showing a power actuated bridging apron without any superposed manually operated apron, and provided with dual hydraulic ram actuators.

Figure 30 is a sectional view in elevation taken substantially along line XXX-XXX of Figure 29.

Figure 31 is a fragmentary sectional view in elevation taken substantially along line XXXI-XXXI of Figure 29.

Figure 32 is a schematic diagram of the hydraulic circuit showing the hook-up for the single and also the dual hydraulic ram actuator.

The structure selected for illustration is not intended to serve as a limitation upon the scope or teachings of the invention, but is merely illustrative thereof. There may be considerable variations and adaptations of all or part of the teachings depending upon the dictates of commercial practice.

The present embodiment comprises a loading ramp or movable platform in the form of a substantially rectangular metallic surface member which is reenforced along its edges by a depending frame 11. The frame 11 is preferably, though not essentially, shaped from channelled U-beams 12 which are welded or otherwise attached to the metallic surface member 10 in the region of the periphery thereof (Figures 1 to 4).

The frame 11 is preferably reenforced with cross beams 13 (Figures 1 and 2) which are welded or otherwise attached to the lower edges of the frame 11, the number and size thereof depending upon the loads to be carried and the dictates of commercial practice. The frame 11 is further reenforced with spaced pairs of longitudinal double or U-shaped beams 14 and single beams 15 (Figure 1) that are inwardly disposed and spaced parallel to the long sides 16-17 to bridge the short sides 18-19 of the frame 11. The beams 14-15 are disposed within the plane of the platform frame 11 above the cross beams 13 (Figures 1 and 2).

The U-shaped longitudinal pairs of beams 14 are oppositely disposed outside of the single beams 15 to receive mounting pins 20-21 therebetween. The pins 20-21 extend through the parallel surfaces of the U-beams 14 having parallel depending spaced walls which confront each other to provide a space sufficient to receive the extremities 22-23 of hydraulic rams 24-25, in this instance two, movable in cylinders 26 27. To this end, the ram extremities 22-23 are provided with transverse bores to 57 loosely receive the pins 21-22 therethrough. Suitable fasteners project through the ends of the pins 2122 to retain the hydraulic rams 24-25 operatively connected to the loading ramp 10 at a position forward of its transverse center line and proximate the forward frame edge 18 of the loading ramp 10 between the double or U-shaped beams 14.

The hydraulic cylinders 26-27 are each provided with an anchoring link 28 at their lower extremities (Figure 2) for reception between upstanding spaced bracket ears or plates mounted on a substantially U-shaped frame 31 (Figures 1, 17, and 18) having upstanding arms 32-33. The bracket 31 is anchored in the bottom 34 of a con- .crete shallow pit 35. The substantially U-shaped bracket 31 together with the hydraulic actuators 22-23 serve as frame 39 constituting a nose rail for the stationary platform 40 which outlines the pit 35. The sling frame 31 is prefabricated from channelled iron beams provided with openings 41 therein to lighten the construction and to receive concrete therethrough. The prefabricated sling frame 31 is preferably embedded in the pit forming concrete before the setting thereof thereby anchoring the prefabricated sling-type bracket 31 with the pit frame 39 in a predetermined position. The prefabricated sling frame is provided with spaced pairs of ears or plates 42-43 for the connection of the lower ends 28 of the hydraulic cylinders 26-27 against displacement other than their pivotal movement. The hydraulic cylinders 26-27 are pivotally mounted on pins 44 that project through the spaced ears or bracket plates 42-43 and the cylinder anchoring ends 28. The lower end ram cylinder pins 44 extend through aligned apertures 45 (Figure 18) in the spaced ears 42-43 to serve as a pivotal mount for the rain cylinders 26-27. The sling frame 31 provides a prefabricated unit which is readily attached to the prefabricated pit frame 39 that is drilled at the factory for ready connection of the sling arms 32-33 thereto.

The rigid movable loading ramp 10 is pivotally anchored to raise and lower as a unit by reason of the hinge loop members 45-46 which are alternately attached to the short side member 19 of the frame 11 and to a reenforcing metallic angle nose 47 comprising part of the substantially U-shaped stationary platform frame 39 that reenforces the exposed rectangular edge of the pit 35.

The hinge loop members 45 are welded or otherwise attached to the rearward movable platform frame beam 19 while the hinge members 46 are anchored to the reenforcing nose 47 by means of threaded fasteners such as studs 48 so that the hinge loops 45-46 are in axial alignment to receive a hinge pin49 therethrough. A central spacer tube 50 idles on the hinge pin 49 to serve as a spacer between the complemental hinge loops 45-46 on both sides thereof. A set screw 51 may be provided through the tube 50 to engage the pin 49 to pivot therewith should this be considered desirable. In this manner, the loading ramp 10 is pivotally mounted for movement to an extreme upward inclined and downward inclined position relative to a horizontal position in alignment with the stationary platform 40 within the pit 35, so that the top surface of the ramp 10 is level with and in the same plane with the stationary loading platform 40.

By resort to the hydraulic actuators 26-27, the movable platform 10 can be pivotally raised or lowered in a clockwise and counterclockwise direction, respectively (viewed from Figure 2) so that it may extend to a truck or freight car floor or other movable platform 52 (Figure 2) to enable the wheeling of hand trucks thereto by traversing the ramp 10 that bridges the intervening space between the fixed loading platform 40 and the truck or freight car floor 55. The movable loading ramp or platform 10 may, in its lowermost position, be limited to assume a horizontal position complemental to and in the plane of the stationary platform 40 to provide surface continuity therewith should commercial practice so dictate. To this end, a horizontal stop plate 53 may be provided across the open end of the pit 35 (Figure 2) to provide support for a member provided on the ramp 10 as will be presently described.

Obviously, a small space must be allowed for between the forward loading platform edge 13 and the truck or freight car platform 52 (Figure 2) in order to avoid contact therebetween during the use thereof. So that the free space between the ramp edge 18 and the movable platform 52 may be traversed by hand trucks or other displacing means, a plurality of bridge plates 54, 55, 56, 57, and 58, in this instance five, are pivotally connected to the forward ramp edge 18 by means of hinges 59 attached to each through which a pin 60 extends.

The hinge pin 60 extends through hinge loops 61 and 62 alternately welded or otherwise fixed to the forward channel 18 of the loading platform frame 11 and the bridge plates 54, 55, 56, 57, and '8, thereby independently connecting the latter to the loading ramp 10. To this end, some of the hinges 62 are sectional to conform with the separation between adjacent bridge plates 54 to 58 inclusive. When the ramp 16 is not in use, the bridge plates 54 to 58 are allowed to drop in a hanging position within the pit 35 to serve as closure for the forward open end thereof and to rest against the horizontal stop 53 to normally maintain the loading ramp or platform in horizontal alignment. Before raising the ramp 10, the bridge plates 54 to 58 are hinged upwardly to assume the dotted line position shown in Figure 2 and thereafter dropped for support on the movable platform or truck floor 52 when it is in loading position relative to the ramp 10. A separate control spacer tube 63 is disposed on the hinge pin 60 to idle thereon except for a set screw 64 which attaches the spacer tube 63 to the hinge pin 60 for rotation therewith.

The separately hinged bridge plates 54 to 58 provide some flexibility as to varying widths of truck or freight car floors 52 or to compensate for any error made by the driver when the truck or trailer is backed into loading position adjacent the ramp 10.

While the bridge plates 54 to 58 in their lowered position gravitate in the path of the cross bar stop 53 and always insure the return of the loading ramp It) to its correct inoperative initial horizontal position without any load on the hydraulic mechanism 26-27, these may be pivotally displaced outwardly or inwardly of the stop bar :2

53 to permit the ramp 10 to be inclined downwardly whenever a truck floor 52 is lower than the stationary platform 49.

In the modified embodiment shown in Figures 5 to 10 inclusive, the central loading ramp 10 is similar in construction to the ramp described in the preceding embodiment; however, two additional shorter hinged loading ramps 65 and 66 are mounted on each side of the primary ramp 10 for hinged connection along the rearward edge 47' of the substantially U-shaped frame 39 which re enforces the opening in the stationary platform 40. The sectional ramps 10-65-66 are useful for freight car loading and unloading, and it should be noted that the side loading ramps 65-66 are of lesser depth than the central ramp lltl to which the actuating hydraulic ram cylinders 26-27 are attached. In this embodiment, the lower ends 28 of the ram cylinder 26-27 are pivotally connected to ears 42-43 which are formed integral with or attached by welding or otherwise to vertical channel bars 32'-33 that are set into the vertical a.

concrete wall 34' (Figure 11) or the pit 35'. Suitable anchoring rods 31' may be joined with the vertical channels 32'-33' to insure the proper anchoring thereof in the concrete 34 before the setting thereof. In this em bodiment the central loading platform 10 has three bridge plates 54'-55'-56' hingedly connected thereto to normally gravitate to a vertical position in the path of an angle iron nose plate 53 (Figure 11) which reenforces the open lower edge of the pit 35 to serve as a support for the bridge plate 5455'-56 which effects contact therewith as the loading ramp 10 is lowered to its initial horizontal position. This insures alignment of the loading ramp 10' with the stationary platform The side ramps 55-56 have, in this instance, single unitary bridge plates 57-58 that are hinged to the for ward edges thereof in the manner described supra and these extend for a distance somewhat narrower than the loading ramps 55-56 that have their side edges 67-68 the central ramp 10 will permit the side ramps -66 to pivotally gravitate downwardly within the limit of the movement of the central ramp it) which serves as the pivotal actuator and control for the side ramps 65-66.

In other words, the pivotal elevation of the central ramp 10' will cause a corresponding pivotal elevation of the side ramps 65-66 by reason of the overlapping plates 67 comprising surface members of the side ramps 65-66 which rest on the side members of the frame 11' (Figure 9) of the central ramp It). The lowering of the ramp 10 by control of the hydraulic circuit to the ram cylinders 26-27 will permit the side ramps 65-66 to gravitate therewith and the central ramp 10' will thus serve to limit the free descent of the side ramps 65-66. It should be noted that the central ramp 10' with its side ramps 65-66 can be elevated to a vertical position as illustrated in dotted outline in Figure 11. This arrangement has particularly advantageous utility in conjunction with railroad loading and unloading facilities where the openings in the freight cars vary depending upon the type of the cars.

In order to support the ramp 10' in its inoperative lowermost position within the pit 35' so that the surface thereof and of its side ramps 65-66 is in alignment with the fixed horizontal platform 4%, angles 69 (Figure 10) are welded or otherwise attached to a suspension corner plate 70 comprising a part of the nose curb 71. The horizontal portion of the angle 69 will always insure the return of the loading ramp it) with its side supported auxiliary ramps 65-66 to their correct inoperative initial horizontal position without any load on the hydraulic mechanism 26'-27'.

In the still further modified embodiment shown in Figures 12 to 16 inclusive, the ramp construction is essentially similar to that shown in Figures 1 to 3 inclusive, save that the ramp 10 comprises slidable and extensive sections 72-73 which are mounted on adjacently disposed and relatively slidable longitudinal beams 74 and 75-75, respectively, which are fixed to the under-side of the sectional ramp plates 72 and 73. The longitudinal beams 75 which are fixed to the ramp section 73, are preferably though not essentially substantially l-shaped crosssections and the horizontal plates 76 fixed to bars 77 serving as supports therefor, are carried by cross-beams 73. The ramp section 72 carries the longitudinal channel members 74 that preferably confront each other on both sides of the I-beam 75 of the ramp section 73 so that the latter will be guided between the former. The cross beams 78 are fixed to the frame 11" of the ramp section 72, and depending side plates 79-80 that extend from the ramp frame 11, serve to overlap side channel members 81-82 as at 83-84 (Figure 15). The side channels 81-82 comprise part of the frame which defines and supports the ramp section 73.

An insert plate 85 conforming substantially in width with the ramp sections 72-73, is capable of positioning between the ramp sections 72-73 (Figure 12) when they are in their extended position, thus providing a substantially elongated ramp it)" having a smooth uninterrupted top surface. Such an extensible ramp is especially eflicacious where the vehicles to be loaded or unloaded cannot approach the fixed platform sufficiently near for the bridge plates 54"-55"-56 to extend over the intervening gap. This would be especially true in fixed railroad sidings where the freight car cannot be moved at will, and the required clearance to the loading platform is such as to preclude the bridge plates 54"-55"-56" to extend thereover. In this embodiment the hydraulic rams 26-27 are pivotally disposed between the prefabricated sling frame 31" and the frame 11" of the fixed ramp section 72 as described in connection with the preferred embodiment Figures 1 to 3 inclusive. As described supra the extensible ramp 10" is hinged to the fixed platform frame end member 47 through the medium of the alternately disposed hinge loops 45"-46". The hinge loops 45"-46 are Welded or otherwise attached to the ramp frame 11 and to the end member 47" of the nose curb frame 39 which defines the opening of the pit The hydraulic mechanism for actuating and controlling the ram cylinders 26-27, 26'-27', and 26"-27 is conventional except for the feature of providing a separate hydraulic circuit and valve for each ram cylinder 26-27. The hydraulic instrumentalities include a base 88 (Figures 20 to 24) formed, in this instance, of an angular bracket member 89 for attachment to a wall or the like. An electric motor 90 is fixed to the base 88 for connection of its armature shaft 91 with a pump 92 that has a pair of upstanding brackets 93-94 to support a tank 95 serving as a fluid reservoir for the hydraulic system.

A pipe 96 connects the vented tank or reservoir 95 with the intake of the pump 92 while a pipe 97 connects the tank 95 with the outlet thereof to maintain a flooded system. A compound valve assembly 98 is mounted on its only base bracket 99 for attachment to a wall or post near the ramp 10, 10, or 10 to be operated or controlled. The valve assembly 98 comprises a housing 100 wherein rotary multiple valves 101-102 are journalled to open or close separate fluid circuits 103 and 104 which individually lead to the ram cylinders 26-27, respectively (Figure 24).

The valves 101-102 are provided with levers 105- 106 that have integral elongated handles 107-103 for efiecting the rotary actuation thereof. The handles 107-108 are connected together by means of spacer tubes 109-110 through which bolts 111-112 extend for operation or actuation of both valves 101-102 in unison with a single manual actuation. Springs 113-114 are anchored between the lever hubs 105-106 and the pump housing 100 (Figure 22) to normally urge the valves 101-102 to their normally closed position to maintain the ramp 10 in its initial horizontal alignment with the fixed platform 40. While the schematic wiring and hydraulic circuits are illustrated in Figure 24 for a two ramp set-up, it should be understood that the same arrangement is applicable to a single or any multiple ramp system.

The manual electric start-stop switches 115-116 are connected in parallel to the power line 117 in a multiple set-up illustrated in Figure 24 to control the motor 90 that is of either sufiiciently slow speed for direct connection to the high pressure pump 92 or of high speed for connection thereto through a speed reducer (not shown). The punip 92 may be any standard type which receives its oil from the tank 95 of any suitable size. It discharges the oil under pressure to a three position lever operated valves 101-102 of standard construction which control the flow to the high pressure hydraulic rams 22-23 and cylinders 26-27 (Figure l) of which there may be two or more for each loading ramp 10. In the present embodiment, there are two rams 26-27 for each ramp 10, 10', or 10".

When the handle 107 of the valves 101-102 is in a neutral position (Figure 22) the oil by-passes through the valves 101-102 and returns to the tank 95 via the easing or housing of the pump 92 where it is used as a lubricant. When the valve handle 107 is moved clockwise (viewed from Figure 22), the return port in the valves 101-102 is closed. The oil is then forced into the hydraulic cylinders 26-27 to expel the rams 22-23 therefrom and raise the loading ramp 10 to an inclined position (Figure 2). This inclination may be varied within the range of tiltable movement of the loading ramp 10 so that its forward ramp edge 13 may be aligned with a truck fioor 52 of any elevation from the road whereon it travels. The oil is held in the cylinders 26-27 by a check valve provided in the discharge part of the corn trol valves 101-102 to hold the loading ram 10 in any predetermined position of inclination within its tiltable range.

When it is desired to lower the ramp 10, the valve handie 107 is moved in a counterclockwise direction (viewed from Figure 22). This movement releases the check valve and allows the oil to flow out of the cylinders 26-27 through the valves 101-102 and back into the tank 95 along with the discharge from the pump 92. It should be noted that two or more ramps 10, or 10 or 10 may be operated by one pump 92 by placing a corresponding number of valves 101-102 in a parallel circuit system. By various positioning of the rams 22-23 relative to the forward edge 18 of the loading ramp 10 or 10" and increasing the length of the latter, any reasonable height can be reached by the end 18 of the loading ramp 10 or 10". Should commercial practice so dictate, the loading ramp 10 may be mounted on wheels so that it can be moved to any position on a loading platform and by suitable braking means or instrumentalities fixedly held stationary relative to any truck floor 52. The operation of the rams 26-27 may be accomplished with a standard hand pump in lieu of the power operated pump 92 should commercial practice so dictate.

The further modified embodiment shown in Figures 25 and 27 is similar in construction and comprises component parts substantially as illustrated and described in connection with Figures 1 to 4 and 12, and like parts have been identified with like numerals except for the distinguishing letter a so that the present description thereof would be more or less repetitious. However, this modified embodiment includes an additional apron 118 which is, in this instance, of substantially the same width as the center manually operated apron 54a, but is or" substantially greater bridging depth or length to facilitate loading between docks and boats or other situations where the gap between the fixed dock and the movable vehicle is substantially greater than the normal manual aprons 5411-5511-5641 can possibly extend.

These unusually large gaps between fixed and movable platforms require an especially heavy as well as large apron 118 that cannot be satisfactorily operated by one or even more men with any degree of efi'iciency from a time and labor standpoint. Such extended aprons 118 require reenforcing structural elements 119 to preclude the yielding thereof under substantial loads. The reenforcing members 119 are welded or otherwise attached to the under side of the apron 118 to increase the load bearing characteristics thereof.

In order to provide for the attachment of a power actuator to the apron 118, the under side of the latter is also provided with spaced bracket plates 120-121 along a median line thereof to pivotally receive a ram 122 therebetween for connection through av pinion 123. The ram 122 operates within the hydraulic cylinder 124 that has its fixed elongated end bracket 126 (Figure 28) fitted with a fixed pintle 127 as projects from both sides thereof. T he pintle 127 extends through and is journalled in bearings 128-129 welded or otherwise fitted into confronting relation to face bracket plates 130-131. 'The bracket plates 130-131 are welded or otherwise attached to channels 132-133 suitably anchored to the under side of a loading ramp plate 10 As shown, the channels 132-133 have angles 134-135 welded or otherwise attached thereto (Figures 28) so as to provide a durable and substantial depending bracket 132-134 and 133- 135 to which the bearing brackets 130-131 are welded or otherwise securely attached. This provides a depending pivotal mount for the ram cylinder 124 that actuates the extended apron 118 to its horizontal operative or vertical inoperative position.

Of course, suitable hydraulic controls provide for positioning the apron 113 in any position between these limits.

In the further modified embodiment shown in Figures 29 to 31 inclusive the structure is substantially identical with the exception that the power actuated ramp 118' is substantially longer than that shown in the previous embodiment and is fitted with dual power actuators 124'125' having their rams 12 2 fitted to bracket plates 12 0'-121 to the pinion 123. With this arrangement, an unusually heavy ramp 118' can be pivotally displaced between the horizontal operative and the vertical inoperative position. This type of ramp 118 is especially adaptable to ship loading and unloading so that manually operated suppplemental aprons such as shown in the previous embodiment are not usually provided in such installations.

In the schematic hydraulic circuit diagram shown in Figure 32, the power actuated aprons 118-118 (shown in parallel pairs) are actuated by the ram cylinders 124124' and these are incorporated into the hydraulic circuit of the type illustrated and described in Figure 24. There are also superimposed in the schematic hydraulic circuit, the dual ram cylinders 124'125 so that either or both can be incorporated into such a system, depending upon the requirements of any particular installation.

While I have illustrated and described a preferred embodiment of this invention, it must be understood that the invention is capable of considerable variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

I claim:

1. In a self-contained loading ramp, the combination with a stationary frame, of a movable platform hinged to said stationary frame along one edge thereof, there being an open pit below said movable platform and contiguous with said stationary frame, a sling type bracket extending along the bottom and confronting walls of said pit, means connecting said sling type bracket to said frame, means for anchoring said sling type bracket to said pit, and hydraulic means pivotally interposed between said sling-type bracket and platform to hingedly raise and lower said movable platform relative to said stationary frame.

2. In a self-contained loading ramp, the combination with a stationary frame, of a movable platform hinged to said stationary frame along one edge thereof, there being an open pit below said movable platform and contiguous with said stationary frame, a sling type bracket extending along the bottom and confronting walls of said pit, means connecting said sling type bracket to said frame, means for anchoring said sling type bracket to said pit, an apron adjustably connected to the opposite edge of said platform to bridge the space with a vehicle floor, means to support said platform in the plane of said stationary frame when said hydraulic means are in their initial inactive position, and power means including a sling-type bracket confined within and interposed between said stationary frame and platform to hingedly raise and lower said movable platform relative to said stationary of said platform to bridge the space with a vehicle floor,

and hydraulic means confined within and pivotally interposed between said sling-type bracket and movable platform to hingedly raise and lower said platform relative to said stationary frame.

4. In a self-contained loading ramp, the combination with a stationary frame, of a movable platform hinged and normally complemental to said stationary frame along one edge thereof, there being an open pit below said movable platform and contiguous with said stationary frame, a sling type bracket extending along the bottom and confronting walls of said pit, means connecting said sling type bracket to said frame, means for anchoring said sling type bracket to said pit, an apron adjustably connected to the opposite edge of said platform to bridge the space with a vehicle floor, and power means comprising hydraulic rams pivotally connected between said sling-type bracket and platform to hingedly raise and lower said platform relative to said stationary frame.

5. In a self-contained loading ramp, the combination with a stationary frame, of a movable platform hinged to said stationary frame along one edge thereof, there being an open pit below said movable platform and contiguous with said stationary frame, a sling type bracket extending along the bottom and confronting walls of said pit, means connecting said sling type bracket to said frame, means for anchoring said sling type bracket to said pit, an apron consisting of a plurality of individual sections adjustably connected to the opposite edge of said platform to bridge the space with a vehicle floor commensurate with one or more of said apron sections, and power means hingedly connected and interposed between said. sling-type bracket and platform to hingedly raise and lower said platform relative to said stationary frame.

6. In a self-contained loading ramp, the combination with a stationary frame, of a movable platform hinged to said stationary frame along one edge thereof, an apron consisting of a plurality of individual sections adjustably connected to the opposite edge of said platform to bridge the space with a vehicle floor commensurate with one or more of said apron sections, there being an open pit below said movable platform and contiguous with said stationary frame, asling type bracket extending along the bottom and confronting walls of said pit, means connecting said sling type bracket to said frame, means for anchoring said sling type bracket to said pit, and power means comprising hydraulic rams pivotally connected between said sling-type bracket and platform to hingedly raise and lower said platform relative to said stationary frame.

7. In a self-contained loading ramp, the combination with a frame, of a series of adjacent movable platforms hinged to said frame along one edge thereof, there being an open pit below said movable platform and contiguous with said stationary frame, a sling type bracket extending along the bottom and confronting walls of said pit, means connecting said sling type bracket to said frame, means for anchoring said sling type bracket to said pit, power means comprising hydraulic rams pivotally connected between said sling type bracket and one of said platforms, and means on said adjacent platforms to engage with said hydraulically operated platform to hingedly raise and lower said series of adjacent platforms relative to said stationary frame.

8. In a self contained loading ramp, the combination with a stationary frame of a platform hinged to said stationary frame along one edge thereof, there being an open pit below said movable platform and contiguous with said stationary frame, a sling type bracket extending along the bottom and confronting walls of said pit, means connecting said sling type bracket to said frame, means for anchoring said sling type bracket to said pit, an apron consisting of a plurality of individual sections adjustably connected to the opposite edge of said platform to bridge the space with a vehicle floor, power means operatively connected to certain of said apron sections to raise and lower the latter relative to said platform, and power means interposed between said sling type bracket and platform to hingedly raise and lower said platform relative to said stationary frame.

9. In a self-contained loading ramp, the combination with a stationary frame, of a platform hinged to said stationary frame along one edge thereof, there being an open pit below said movable platform and contiguous with said stationary frame, a sling type bracket extending along the bottom and confronting walls of said pit, means connecting said sling type bracket to said frame, means for anchoring said sling type bracket to said pit, an apron consisting of a plurality of individual sections adjustably connected to the opposite edge of said platform to bridge the space with a vehicle floor, a hydraulic power actuator interposed between one of said apron sections and the platform hinged therewith to raise and lower the latter relative to said platform, and power means comprising hydraulic rams pivotally connected between said sling type bracket and platform to hingedly raise and lower said platform relative to said stationary frame.

386,355 Sheild July 17, 1888 12 Tullock et al Feb. 11, 1902 Bidlake Aug. 4, 1914 Love Oct. 6, 1914 Hillier Mar. 7, 1916 Wood Oct. 12, 1926 Morgan Apr. 25, 1933 McEwen et al Aug. 1, 1944 Haynes Mar. 27, 1945 Powers Feb. 17, 1948 Astry July 10, 1951 Flippin Sept. 18, 1951 

